Abstract

we show for the first time that biaxial crystals exhibit continua of directions of propagation where the absorption coefficient is the same for the two associated polarization modes. This statement is supported by both calculations and experimental data obtained in Nd:YCOB.

Figures (3)

Polar representation in the dielectric frame (x, y, z) as a function of the θ angle of the absorption coefficients α+(θ,φ) and α-(θ,φ) relative to the two polarization modes at 0.812 µm in four planes containing the z-axis at different φ angles. The circles stand for the data recorded in a 7.44-mm-diameter Nd:YCOB sphere ; the continuous lines are calculated curves. The concentric circles stand for the polar scale in 2, 4 and 6 cm-1 giving the magnitude of the absorption coefficients

Spherical coordinates of the direction of propagation for which the magnitude of the absorption coefficient is the same for the two polarization modes. The circles correspond to the experimental data recorded in a 7.44-mm-diameter Nd:YCOB sphere, the black ones corresponding to the intersection dots Ai and Bi, with i=1, 2, 3 and 4, defined in Fig.1. The continuous lines are calculated curves.